Double Towing

You can't backup, and I doubt you will be able to see the jet ski or trailer back there unless you decide to go with a wireless camera behind the toad. Safe, depends on you, I have seen a tricycle with a drunk adult crash and injure a few folks, yet put a 5 yr old on it and they do just fine. I have a DP, and pull my D/A, is it safe, yes, would I put something else behind it, no, but I am not you.

I found a maximum length of sixty five feet but I can't find anything on brakes, not yet at least.

All the legal aspects aside, I was wondering what people thought of this particular set up, if its safe or not. I don't see a problem however I have never towed a car on a dolly much less having said car pulling a trailer too.

Some states specify that the second trailer must be equipped with brakes which can be controlled by the driver.
What does YOUR state say?
Again, reciprocity probably does not apply!

Legal and length I'll be ok, I was more interested if towing this way, with the car on the dolly and the jet ski hooked to the car was safe or are there some safety concerns I don't know about.

Lengthwise, if you are in a state allowing double towing, you should be all right. Just be sure to measure each one, add together, and be sure you are under 65'.

And, as mentioned, this is state specific, and you will NOT be able to go into all states.

I sold my fiver a couple years ago and haven't been on the board much however we are about to purchase a Forest River Sunseeker 3050 which is a Class-C motorhome. It's equipped with a 7,500 pound hitch.

What I was wondering was if it was safe to put my car on a KarKaddy and tow the Jet Ski hooked to the ball on the car. I believe I can legally double tow in Texas I was just wondering if it was safe doing so. We have thought about trailering both but then we would have a 28 foot trailer and even an all aluminum trailer would be to heavy

Your profile shows you have a 5th wheel not a motorhome. If you've changed to a motorhome more information would be helpful. If you now have a class A or C gas powered motorhome the maximum towing capacity would be 5,000 lbs. Many models only have a 3,500 lb. towing capacity.

Tandem tow dollies generally weigh between 800 lbs. and 1,000 lbs. The car itself weighs between 3,300 lbs. and 3,600 lbs. depending on year and options.

A jet Ski weighs in the neighborhood of 800 - 1,000 lbs. The combination will run in the neighborhood of 4,900 lbs. to 5,700 lbs.

If the combination is on the lighter side it's touch and got for a motorhome with a 5,000 lb. towing capacity, and a definite no go for one with a 3,500 lb. towing capacity. If you have a DP with a 10,000 lb. towing capacity it shouldn't be a problem

Wait you are in Texas. I've seen a Chevy truck,pulling a toyota truck, hooked to an older Buick that had a loaded large utility trailer going the the hills outside of Fort Stockton. Worse yer I seen it again (different car and truck) loading to the gills not more than 100 miles later.
The family was spread between the front trucks.

If the car and the jet ski are on the car dolly properly secured that would not be a double tow. You are only towing the car dolly.